DENVER - School officials who banned a 6-year-old transgender girl in Colorado from using the girls' lavatory have declined to take part in mediation of the civil rights complaint brought by her parents, the two sides said on Friday.

First-grader Coy Mathis, who was born male but identifies as female, had been using the girls' restroom at Eagleside Elementary School near Colorado Springs until late last year, when the principal informed her parents she would no longer be permitted access to the girls' facilities.

Instead, she was restricted to using either the boys' restrooms or gender-neutral facilities reserved for employees or those in the school's health room, her parents said.

The parents and lawyers representing the family urged the principal to reconsider, contending that singling out their daughter as the only girl in the school barred from using the girls' bathrooms was stigmatizing and psychologically damaging.

They also asserted that the restriction violated the state's anti-discrimination laws and asked school officials to at least maintain the status quo -- allowing Coy to keep using the girls' restroom -- until both sides had a chance to discuss the issue.

But responding to the family by letter in late December, the school district defended its actions as consistent with state law and refused to back down.

The district gave little explanation of its position except to state that it "took into account not only Coy but other students in the building, their parents, and the future impact a boy with male genitals using a girls' bathroom would have as Coy grew older."

The girl's parents, Kathryn and Jeremy Mathis, then took their daughter out of Eagleside to home-school her and filed a complaint last month with the Colorado Civil Rights Commission.

The family's lawyer, Michael Silverman, said the first step in seeking to resolve such a complaint is to see if both sides will agree to mediation, which the Fountain-Fort Carson School District declined to do.

"We are shocked that her school will not even meet to talk about this so that Coy can quickly return to school," said Silverman, executive director of the Transgender Legal Defense and Education Fund. He said the commission would now open a lengthy inquiry into the case.

The school district, which has until mid-March to formally answer charges in the complaint, acknowledged having declined mediation, a step it said "would be unproductive." But it said the parents had refused to meet with school officials when the matter first surfaced in December.

"The parents consistently indicated ... that they would file a discrimination charge if the district did not completely acquiesce to their demands," the district said in a statement. It also said the family had been unwilling to discuss "reasonable proposals" to resolve the dispute.

The parents' complaint asserts that the district violated a state law that bars schools from denying individuals access to public accommodations because of their sexual orientation or transgender status.

They also have cited anti-discrimination regulations issued by the state Civil Rights Commission that specifically require schools to allow transgender students access to "gender-segregated facilities that are consistent with their gender identity," including restrooms, locker rooms and dormitories.

The parents said in a statement on Friday that in limiting their daughter to the boys' lavatory, a gender-neutral employee restroom or the bathroom in the school's health clinic the district was inviting mistreatment of their daughter by classmates.

"Coy is not sick, she is not an adult, and she is not a boy," the statement said. "We are saddened that her school will not even come to the table to talk about this issue."

But the district said the proper forum to discuss the issue is in the "process initiated ... by the parents," and not in the news media.

School officials who banned a 6-year-old transgender girl in Colorado from using the girls' lavatory have declined to take part in mediation of the civil rights complaint brought by her parents, the two sides said on Friday.